Every year, over 6000 healthy individuals donate a kidney in the United States to benefit a loved one or even a stranger. Currently, approximately 100,000 individuals are living post-nephrectomy. Live kidney donors gain no medical benefit from donation, nor do they expect to. However, live donors do expect the medical community to understand the long-term risks of kidney donation, for the purposes of donor selection, informed consent, and post-donation care. For African American kidney donors, we have thus far failed in this regard. The largest cohort study of kidney donors, from which the transplant community's assessment of the safety of kidney donation has been primarily derived, was comprised of less than 1% African American donors. Yet 13% of live donors in the US are African American, and our preliminary findings suggest that rates of death, hypertension, chronic kidney disease, and end-stage renal disease following donation are significantly higher in African Americans. It is critical to not only estimate the risk of these diseases, but to understand the risk attributable t donation; however, no study to date has captured appropriate non-donor controls that are necessary for this estimation. Furthermore, many African American donors, particularly young donors, have limited access to healthcare, and it is important to elucidate potential disparities i the management of post- donation consequences such as hypertension and decline in kidney function. In light of a significant knowledge gap regarding long-term outcomes and medical care following kidney donation in African Americans, we propose to estimate the incidence and consequences of hypertension and kidney disease in African American versus Caucasian donors. More importantly, we will determine how much of that risk is attributable to donating a kidney (rather than population-based differences in underlying risk) by comparing donors to healthy non-donors. We will also evaluate the reliability of administrative data sources in capturing and studying post-donation morbidity, and seek to better understand racial differences in treatment patterns for donors who develop hypertension or chronic kidney disease. We will accomplish these goals by recruiting the largest primary cohort of African American donors (over 4000 donors from the top 13 centers in the US), a comparison cohort of Caucasian donors, and healthy non-donors who met eligibility criteria for donation but did not actually donate. We will supplement these cohort with linkage of national registry data to Medicare, Medicaid, and private payer claims and pharmacy data. Our findings will have a direct impact on the practice of live kidney donation among African Americans in the US, informing critical aspects of donor selection, informed consent for donation, and post-donation care. In addition, this research will create an important resource from which several future ancillary projects are foreseeable, including genotyping to risk stratify potential donors, evaluating the effects of acut kidney injury and nephrotoxic drugs after donation, and estimating lifetime healthcare costs and utilization for kidney donors.